Re: [ndctl PATCH v4 6/9] cxl/region: Add cxl-cli support for DCD regions

[Alison Schofield <alison.schofield@intel.com>]

On Sat, Dec 14, 2024 at 08:58:33PM -0600, Ira Weiny wrote:
> CXL Dynamic Capacity Devices (DCDs) optionally support dynamic capacity
> with up to eight partitions (Regions) (dc0-dc7).  CXL regions can now be
> sparse and defined as dynamic capacity (dc).
> 
> DCD region creation requires a specific partition, or decoder mode, to
> be supplied.  Introduce a required option for dc regions to specify the
> decoder mode.
> 
> Add support for dynamic capacity region creation.
> 
> Based on an original patch from Navneet Singh.
> 
> Signed-off-by: Sushant1 Kumar <sushant1.kumar@intel.com>
> Co-developed-by: Ira Weiny <ira.weiny@intel.com>
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> ---
>  Documentation/cxl/cxl-create-region.txt | 11 ++++++++--
>  cxl/json.c                              | 27 ++++++++++++++++++++++-
>  cxl/memdev.c                            |  4 +++-
>  cxl/region.c                            | 39 ++++++++++++++++++++++++++++++++-
>  4 files changed, 76 insertions(+), 5 deletions(-)
> 
> diff --git a/Documentation/cxl/cxl-create-region.txt b/Documentation/cxl/cxl-create-region.txt
> index b244af60b8a63281ed63d0d6f4027ea729ad51b0..a12cc8d3f19fa582376599ecc8512640f15ce42c 100644
> --- a/Documentation/cxl/cxl-create-region.txt
> +++ b/Documentation/cxl/cxl-create-region.txt
> @@ -75,8 +75,9 @@ include::bus-option.txt[]
>  
>  -t::
>  --type=::
> -	Specify the region type - 'pmem' or 'ram'. Default to root decoder
> -	capability, and if that is ambiguous, default to 'pmem'.
> +	Specify the region type - 'pmem', 'ram', or 'dc'.  Default to root
> +	decoder capability including the first of any DC partition found.  If
> +	the decoder capability is ambiguous, default to 'pmem'.

When or why is a root decoders capability ambiguous? 

Is type 'dc' really analagous to 'pmem' or 'ram'?  As a newbie to DCD,
I'd have guessed it would say 'dyn' or 'dynamic' because dc is more
analagous to 'pc' and 'rc' and we don't use those.

-- snip to end
>